The 4MOST consortium invites the astronomical community to a workshop on Science with Large Area Spectroscopic Surveys to develop the specific needs for spectroscopic survey facilities in the next decade. This three-day workshop (13-15 Nov 2012) held at the AIP, Potsdam, will enable discussions between scientists from all astronomical fields from both inside and outside the 4MOST consortium, in order to ensure that the capabilities and observational strategies of 4MOST will satisfy the largest range of science opportunities as foreseen by the broader astronomical community.

Although it is unfortunately too late to register, maybe some among you are planning to go and it would be important then to convey the message that spectropolarimetric data will significantly augment the science legacy of the telescope. If somebody plans to give a talk there, please let me know and if you agree, we could also share your presentation on our website.

Also, there might be more opportunities to discuss the Conceptual Design Study, so we will keep you informed.

We present an approach to spectropolarimetry which requires neither moving parts nor time dependent modulation, and which offers the prospect of achieving high sensitivity. The technique applies equally well, in principle, in the optical, UV or IR. The concept, which is one of those generically known as channeled polarimetry, is to encode the polarization information at each wavelength along the spatial dimension of a 2D data array using static, robust optical components. A single two-dimensional data frame contains the full polarization information and can be configured to measure either two or all of the Stokes polarization parameters. By acquiring full polarimetric information in a single observation, we simplify polarimetry of transient sources and in situations where the instrument and target are in relative motion. The robustness and simplicity of the approach, coupled to its potential for high sensitivity, and applicability over a wide wavelength range, is likely to prove useful for applications in challenging environments such as space.

Study of the Earthshine provides information about what has reflected light coming from the Sun. Indeed, properties are different whether light is reflected off oceans or continents. Light can also be scattered by air molecules, aerosols or cloud particles when passing through the Earth's atmosphere.

Light which has been reflected/scattered becomes strongly linearly polarized. Therefore, using spectropolarimetric observations (measurements of the polarization at several wavelengths or colors), it is possible to detect the spectral signatures of aerosols, clouds, etc...but also from vegetation. European astronomers have used this technique to determine the fractional contribution of clouds and ocean surface. The results are sensitive to visible areas of vegetation as small as 10 per cent.

These results represent a benchmark for the diagnostics of the atmospheric composition, mean cloud height and surfaces of exoplanets, planets orbiting around other stars.

These results have been published in Nature. One of the authors, Dr. Stefano Bagnulo from Armagh Observatory (UK) is an active member of this COST Action.